我承認(rèn)我不是PHP的領(lǐng)導(dǎo)者。然而，在看了一些PHP的信息之后，我認(rèn)為有一些功能需要添加到其中來(lái)處理數(shù)據(jù)庫(kù)連接和整合XML。要做到這一點(diǎn)，我想我可以創(chuàng)建一個(gè)處理連接MySQL和使用PHP中的domxml功能來(lái)提供XML輸出的類(lèi)。然后我就可以在PHP腳本的任何地方聲明這個(gè)類(lèi)并且在需要使用它的時(shí)候可以提供XML功能。

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我假設(shè)人們使用PHP是原因是他的標(biāo)價(jià)：免費(fèi)。MySQL為需要向系統(tǒng)中增加數(shù)據(jù)庫(kù)功能的開(kāi)發(fā)人員提供一個(gè)免費(fèi)的數(shù)據(jù)庫(kù)解決方案。這些解決方案的缺點(diǎn)是在設(shè)置和管理的時(shí)候有些復(fù)雜。

我在這篇文章中使用的PHP版本是PHP 4.3.4 for Win32，可以從The PHP Group下載。MySQL的版本是MySQL 4.0.16 for Win32，可以從MySQL.com得到。MySQL的安裝很容易——只要簡(jiǎn)單地按照其指令來(lái)就可以了。PHP稍微有一點(diǎn)復(fù)雜。

在PHP的下載頁(yè)面有兩個(gè)文件：一個(gè)ZIP文件和一個(gè)安裝文件。因?yàn)槲覀冃枰砑覼IP文件中的擴(kuò)展，所以這兩個(gè)文件都要下載。下面是下載之后的所要做的一個(gè)簡(jiǎn)單步驟：

1. 使用安裝文件安裝PHP。

2. 解壓iconv.dll，將其放到Windows的系統(tǒng)文件夾中。

3. PHP安裝目錄下創(chuàng)建一個(gè)目錄（默認(rèn)為C:\PHP）“extensions”。

4. 解壓php_domxml.dll文件到這個(gè)目錄。

5.? 在Windows文件夾下找到php.ini文件，然后使用記事本或其它文本編輯器打開(kāi)。在這個(gè)文件中找到“extensions_dir=”，然后將其值修改為第3步設(shè)置的擴(kuò)展文件夾的完整路徑。

6. 找到“;extension=php_domxml.dll”，刪除本行開(kāi)頭的分號(hào)。

7.重新啟動(dòng)Web服務(wù)器。

然后在你的Web目錄下使用下面的代碼創(chuàng)建一個(gè)PHP頁(yè)面“test.php”。（這段代碼在運(yùn)行IIS 5.0的Windows 2000 SP3能夠正常運(yùn)行。）

$myxml = new CMySqlXML("localhost", "test_user", "password", "test");

echo $myxml->run_sql_return_xml("SELECT * FROM users");

classCMySqlXML {

??? var $host;

??? var $user;

??? var $password;

??? var $db;

??? functionCMySqlXML($host, $user, $password, $db) {

??????? $this->host = $host;

??????? $this->user = $user;

??????? $this->password = $password;

??????? $this->db = $db;

??? }

????? functionrun_sql_return_xml($sql_string) {

??????? $connection = mysql_connect($this->host, $this->user, $this->password,

$this->db);

??????? mysql_select_db($this->db);

??????? $result = mysql_query($sql_string);

??????? $doc = domxml_open_mem("");

??????? while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {

??????????? $num_fields = mysql_num_fields($result);

??????????? $row_element = $doc->create_element(mysql_field_table($result, 0));

??????????? $doc_root = $doc->document_element();

??????????? $row_element = $doc_root->append_child($row_element);

??????????? for ($i = 0; $i < $num_fields; $i++) {

$field_name = mysql_field_name($result, $i);

$col_element = $doc->create_element($field_name);

??????????????? $col_element = $row_element->append_child($col_element);

??????????????? $text_node = $doc->create_text_node($row[$field_name]);

??????????????? $col_element->append_child($text_node);

??????????? }

??????? }

??????? mysql_free_result($result);

??????? mysql_close($connection);

????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? been have—

users". Also, you will need to create a user to access the data on the test database. For the steps to create databases, tables, etc., you can view the MySQL documentation.

If you analyze the code, you will understand that I created a class called CMySqlXML. The CMySqlXML constructor accepts four parameters: the MySQL host name, a valid user name, a password and a database name. The constructor uses these four parameters to set the host, user, password and db member variables of the class.

The only method provided by this class is run_sql_return_xml(). It accepts a SQL query string parameter. When this method executes, it creates a connection to the MySQL database and selects the database. The query string is executed and the result is stored in the variable $result. Use the domxml_open_mem() function to create a new DOMDocument object. The code then starts looping through all the records in the result set. For each record, add a row element with the same name as the result set's table to the DOMDocument document element. Then add an element to the row element for each field named fieldname. Finally, a text node is added to each field node with the node's value being the value of the field.

After looping through all rows, the code releases the result set and closes the connection. The resulting DOMDocument XML is returned from the function.

At the beginning of the PHP page you will see that the CMySqlXML object is instantiated and the run_sql_return_xml() method is called. The return value of this method is returned to the client. The domxml functions comply with the DOM specification except for the PHP function naming convention.

If you need more information about the DOM specification, you can visit the W3C's site. More information about domxml can be found from The PHP Group, where you can download documents in different formats.

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The author of this article: Phillip Perkins is Ajilon Consulting signee. His experience ranges from machine control and client/server to intranet applications.

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